Padlocks are very widely used in storages, and on gates and doors worldwide, due to its convenience and compact structure, etc. However, some unauthorized individuals try to open a padlock using lock-picking tools or by making an unauthorized key. Since the simple internal configuration of a current padlock, opening the padlock with lock-picking tools or the unauthorized key requires little skills and it only takes very short time for the unauthorized individual to open the padlock, and thus the number of the unauthorized use, theft, vandalism, or harm increases rapidly. There is a growing expressed need for a padlock with higher security.